1. Field of the Invention
This invention relates generally to concrete working machines and more particularly to a novel concrete surfacing machine.
2. Discussion of the Prior Art
In the context of this invention, concrete surfacing refers in a broad sense to performing some type of machining operation on a concrete surface by movement of an appropriate concrete machining tool along the surface. In a more limited sense, concrete surfacing refers to smoothing or planing a concrete surface by movement of a powered rotary surfacing or planing cutter along the surface. A present useful application of the invention, for example, involves surfacing or planing the floors of concrete dam spillways.
In this regard, it has found that high velocity water flow over even small bumps and the like on the floor of a concrete dam spillway causes damage to the spillway in the form of cracking, chipping and other erosion of the concrete. It is thought that this is due to low pressure or vacuum regions and impact forces which are created by the water flowing at high velocity over the bumps. In any event, if this problem is not corrected by removing the bumps, the spillway can suffer irreparable damage and become totally unusable in a relatively short period of time.
Spillway surfacing involves certain unique problems to which this invention is addressed. One problem resides in the fact that some spillway surfaces which require surfacing are inclined often quite steeply, lengthwise and/or laterally of the spillway. As a consequence, a surfacing machine must be capable of operating on steep slopes and hence must have a propulsion or drive system capable of effecting controlled and safe movement of the machine up and down such slopes. Moreover, if the surface slopes laterally of the machine, the latter must be restrained against slipping sideways.
In spillway surfacing operations, a surfacing machine may be required to move back and forth along or across the spillway without turning around at the end of each pass. Accordingly, a spillway surfacing machine should be reversible, that is capable of propulsion in either direction of movement. In addition a dam spillway may have both relatively flat concrete surfaces and curved concrete surfaces which require surfacing. A spillway surfacing machine must thus be capable of operating on, i.e. surfacing, both flat and curved surfaces. As will appear from the later description, each pass of a surfacng machine may involve movement of the machine along both flat and curved surfaces. Accordingly, a spillway surfacing machine must not only be capable of operating on both flat and curved surfaces but, further, must be capable of rapid transition from one shape of surface to another without time consuming adjustment of the machine.
At this point, it is significant to note that while the present invention is concerned primarily with dam spillway surfacing, it is not to be construed as limited to this particular application. In this regard, it will be recognized that the above discussed concrete surfacing problems are not limited to spillway surfacing.